A departing flight typically remains on tower frequency until which of the following?

A departing flight typically remains on tower frequency until clear of the control zone because this ensures effective communication and control during critical phases of the flight, including takeoff and initial climb. The control zone, which is a designated area surrounding an airport, is where air traffic control provides instructions and clearances to ensure the safe separation of aircraft. Once the aircraft is clear of the control zone, it can safely transition to the next phase of flight, at which point it would switch to the appropriate en route frequency or approach control.

Communication with the tower during this period is crucial for pilots to receive updates on traffic, weather, and any last-minute instructions that could impact safety. By remaining on tower frequency until clear of the control zone, pilots can ensure that they are operating within the controlled airspace effectively.